Thermoelectrochemical\nMethod for Quantification of\nthe Micellization Entropy of Redox-Active Polymers

Redox-active micelles undergo reversible association\nand dissociation\nin response to their redox potential and are promising materials for\nvarious applications, such as drug delivery and bioimaging. Evaluation\nof the micellization entropy is critical in controlling the thermodynamics\nof micelle formation. However, conventional methods such as isothermal\ntitration calorimetry and surface tensiometry require a long measurement\ntime to observe changes in the heat flow or the surface tension caused\nby the micellization. Here we report a thermoelectrochemical method\nto quantify the entropy change produced by redox-active micelles.\nA set of poly(ethyl glycidyl ether-<i>b</i>-ethylene oxide)phenothiazine\n(PT-EGE-EO) with varied chain length were synthesized, and their micellization\nentropy was calculated from the temperature-dependent changes of the\nequilibrium potential. This thermoelectrochemical method enables a\nquick evaluation of the micellization entropy with only a single sample\npreparation and temperature sweep. The obtained results showed a reasonable\nagreement with the conventional surface tensiometry and isothermal\ntitration calorimetry, indicating that the thermoelectrochemical method\nis a promising alternative for quantification of the micellization\nentropy.